Multicomponent diffusion in ternary silicate melts in the system K2O-Al2O3-SiO2: I. Experimental measurements
Multicomponent diffusion in ternary silicate melts in the system K2O-Al2O3-SiO2: I. Experimental measurements
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K2O-Al2O3-SiO2 体系中三元硅酸盐熔体的多组分扩散： I. 实验测量
DOI：
10.1016/0016-7037(94)00283-r
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发表时间：
1995
影响因子：
5
通讯作者：
D. Rubie
中科院分区：
文献类型：
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作者：
S. Chakraborty;Donald Bruce Dingwell;D. Rubie
我们测量了空气中 1100–1600°C 的 K2O-Al2O3-SiO2 系统中富硅熔体的多组分扩散系数矩阵 D。在二氧化硅含量恒定（按重量计）的过铝和过碱性组合物中进行测量。成功地采用了一种先前未经测试的方法，用于从单个扩散偶实验中检索完整的扩散系数矩阵 D。研究发现，扩散过程中熔体中不同氧化物组分之间存在显着的耦合。这种耦合可能会导致组件向上扩散。仔细的微探针分析揭示了本研究中所有成分（但不是在同一实验中）都发生了上坡扩散。耦合的本质在另一篇论文中进行了定量处理（Chakraborty 等人，1995）。过铝熔体和过碱性熔体中的偶联性质是相同的。然而，在可比条件下，全碱性熔体的扩散速率要快得多。讨论了 D 矩阵 D;; 的元素与有效二元扩散系数 (EBDC) 之间的关系。结果表明，即使存在强烈的多组分相互作用，也可以用 EBDC 来描述多组分熔体中的扩散。然而，如果不满足某些理论要求，则通过拟合扩散偶实验中获得的浓度分布而获得的EBDC可能会在传质计算中产生虚假结果。
We have measured the multicomponent diffusion coefficient matrix, D, for silica rich melts in the system K2O-Al2O3-SiO2between 1100–1600°C in air. Measurements were done in both peraluminous as well as peralkaline compositions at constant silica content (by weight). A previously untested method for retrieving the full diffusion coefficient matrix, D, from a single diffusion couple experiment was employed successfully. It is found that there is significant coupling between the different oxide components in the melt during diffusion. This coupling may lead to uphill diffusion of a component. Careful microprobe analysis revealed the occurrence of uphill diffusion of all components (not in the same experiment, however) in this study. The nature of coupling is quantitatively treated in a companion paper (Chakraborty et al., 1995). The nature of coupling is the same in peraluminous and peralkaline melts. However, diffusion rates are much faster in peralkaline melts at comparable conditions. The relationship between the elements of the D matrix, D;;, and the effective binary diffusion coefficients (EBDC) are discussed. It is shown that it is possible to describe diffusion in multicomponent melts in terms of EBDC, even if there is strong multicomponent interaction. However, if certain theoretical requirements are not fulfilled, then the EBDC obtained by fitting concentration profiles obtained in diffusion couple experiments may yield spurious results in mass transfer calculations.